Alteration

Spoilers Ahead, You have been warned.

I was somewhat looking forward to Alicization as I hadn't read the light novel unlike the others. That being said, after finishing all the episodes I am wholely dissapointed by this series.

TLDR: Don't watch it, likely theres going to be 24 more episodes, wait for that to release. Otherwise you'll just reach an unsatisfying ending.

The Character Gap

I am fine with regular characters and I enjoy OP characters, Sword Art has this whole thing with pretending Kirito isn't overpowered. Okay, thats fine, but even if he takes a few hits every now and then to outweigh the winning it doesn't make him "Normal". Make him OP or make him realistically normal.

The innescapably slow story progression...

Sword Art Online was 24 episodes, 12 for SAO, 12 for Alfheim.
Sword Art Online II was 24 episodes, 12 for GGO, 12 for Side Stories (going by the thumbnail since i never finished GGO).
Alicization is 24 episodes... and is actually likely going to be 48 episodes when its actually complete, that's a massive time to dedicate to this arc that has overall been pretty generic and slow progressing.